1. Field of the Invention
The present invention relates to a recording apparatus for recording an image on a recording medium in accordance with print data.
2. Related Background Art
A serial type recording apparatus which prints data transferred from a host apparatus on a recording medium has been known. Such a recording apparatus records on the recording medium in accordance with a print command from the host apparatus. Accordingly, when a print speed of the recording apparatus is sufficiently high, a processing speed of the host apparatus becomes critical.
In the serial type recording apparatus, the printing is not started unless one line of data along a scan direction is stored. As a result, if a print data transfer rate changes line by line, a data buffer in the recording apparatus may not be effectively used.
In a color output recording apparatus which has recently been becoming popular rapidly, print data is of huge volume and the low processing speed of the host apparatus and the low data transfer rate are raising a serious problem.
In a recording head having a plurality of recording elements integrally arranged (hereinafter referred to as a multi-head) to improve a recording speed, it is common to provide a plurality of integrally arranged ink discharge orifices and liquid paths, and to arrange a plurality of such multi-heads to comply with a color requirement.
In printing a high resolution monochromatic image or color image, various factors such as coloration, tonality (or gradation) and uniformity should be considered. As to the uniformity, a slight variation from nozzle to nozzle which is caused during the manufacturing process of the multi-head may affect the amount of discharge of ink by the nozzle and the direction of discharge and it finally appears as a scatter of the density of the printed image, which results in the degradation of the image quality. To solve the problem of scatter of density, it has been proposed to print a print area, which may normally be printed in one scan, in a plurality of scans and feed a sheet for each scan (for example, U.S. Pat. No. 4,967,203).
For example, the printing in a first scan is effected while a lower half of a print head is used for a predetermined print area on a record sheet and a mask of zig-zag pattern (or checker flag pattern) is applied to the print data. Then, the sheet is fed by one half of the print head. Then, the printing in a second scan is effected while an upper half of the print head is used and a mask of a complementary zig-zag pattern (or reverse checker flag pattern) is applied with the print data (hereinafter referred to as split recording). By this recording, the affect by the nozzle to produce nozzle scatter of the print head at the designated print area is minimized.
However, since the recording is effected by discharging the ink in the ink jet recording apparatus, the tint may differ between the recording on a dry record sheet and the printing on a wet record sheet. Particularly in the split recording as described above in which one print area is printed in a plurality of scans, the ink is discharged on the wet sheet ink in a second scan.
The recording apparatus usually records on a recording medium by a print command from the host apparatus. Accordingly, when the print speed of the recording apparatus is sufficiently high, the processing speed of the host apparatus becomes critical. If the print data processing speed and the data transfer speed of the host apparatus are lowered in the course of printing, the ink printed in the previous scan is dried and the tint may differ from that of the printing effected before drying and the scatter of density appears in the print and high quality printing is not attained.